The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In order to enhance an exhaust gas, many researches have been performed in a vehicle industry, and particularly, in order to reduce discharge of hydrocarbon (HC) among evaporation gas components of gasoline fuel, foreign countries adapt a regulation that regulates a total amount of a fuel evaporation gas to 0.5 g/day or less and are scheduled to sequentially enlarge a total amount of a fuel evaporation gas to 0.054 g/day or less.
In order to meet the regulation, nowadays, a material of a fuel tank and a connection structure thereof have been improved to reduce occurrence of a fuel evaporation gas that penetrates the fuel tank, and a fuel evaporation gas recirculation apparatus in which a canister is applied to a fuel supply apparatus has been used.
Here, the canister contains an adsorbent material that can absorb a fuel evaporation gas from a fuel tank that stores volatile fuel, and in order to prevent a fuel evaporation gas that evaporates from a float chamber of a vaporizer and the fuel tank from being discharged to the air, the canister is connected with the fuel tank to collect the fuel evaporation gas.
In this way, the fuel evaporation gas that is collected in the canister is again injected into the engine through a Purge Control Solenoid Valve (PCSV) that is controlled by an Engine Control Unit (hereinafter, referred to as an ‘ECU’) to be burned and thus the fuel evaporation gas is recirculated.
The purge control solenoid valve is installed on a purge line and selectively blocks the collected fuel vapor in the canister. An operation of the purge control solenoid valve is controlled by the ECU, and a fuel vapor amount exhausted through the purge control solenoid valve is adjusted by a duty control of the ECU.
In the fuel vapor purge system according to a conventional art, a separate check valve for preventing the fuel vapor from flowing backward on a lower stream of the purge control solenoid valve is additionally installed. The check valve is engaged to a hose to which the fuel vapor flows, in this case, since a connection clip should be separately used and a length of the hose extends to engage the check valve, parts and workers are increased, thereby raising a manufacturing cost.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.